Multiphase inverter circuits provide output electrical power at three or more electrical output phases for powering a multiphase load by alternating operation of high and low side switches connected between DC bus terminals and common for each output phase. Controlling the output of the multiphase inverter typically involves closed loop pulse width modulation (PWM) based on output current feedback information derived from current sensors in the form of shunt resistors connected between a low side switching device and a lower DC bus node. The current through the low side switch is sampled in the on-time during which the low side switch is activated, with the sampling being synchronized with the low side switching control signal. Many inverters utilize insulated gate bipolar transistors (IGBTs) operated at PWM switching frequencies ranging from several kHz to 20 kHz or more. Gallium nitride (GaN) and other faster switching devices allow even higher PWM switching frequencies at 100 kHz and above. However, increased switching frequency creates problems for sampling phase currents using low side current shunt sensors. The voltage across the current shunt is typically sensed using differential amplifiers whose output must settle to within a least significant bit (LSB) of an analog to digital (A/D) converter before sampling can begin to obtain an accurate feedback value representing the low side current. Increasing the switching frequency reduces the on-time pulse width for a given low side duty cycle percentage, and thus allowing sufficient time for amplifier outputs to settle before sampling becomes difficult. Moreover, back EMF from certain loads increases with inverter output speed, and the inverter control loop must compensate by increasing the individual phase output voltages through decreased low side duty cycles. Increases in the bus voltage level at the input of the inverter and/or limiting the maximum inverter output frequency may address the back EMF and reduced on-time issues, but these approaches are undesirable from a system performance perspective. Also, high performance sensing amplifier circuitry can be used, but this adds cost. Accordingly, a need remains for improved methods and apparatus for operating multiphase inverters to facilitate accurate feedback sensing using low side current shunts to facilitate higher PWM switching frequencies without increasing system cost or complexity.